#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>    // close()
#include <arpa/inet.h> // inet_pton()
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main()
{
    // 1. 创建socket
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd < 0)
    {
        perror("server socket create");
        exit(1);
    }
    // 2. 绑定地址和端口
    struct sockaddr_in server_addr;
    int server_len = sizeof(server_addr);
    memset(&server_addr, 0, server_len);
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = INADDR_ANY;
    int res = bind(server_fd, (struct sockaddr *)&server_addr, server_len);
    if (res < 0)
    {
        perror("server bind");
        close(server_fd);
        exit(1);
    }

    // 3. 监听连接
    res = listen(server_fd, 5);
    if (res < 0)
    {
        perror("server listen");
        close(server_fd);
        exit(1);
    }

    // 4. 接受连接
    struct sockaddr_in client_addr;
    int client_len = sizeof(client_addr);
    int new_socket;
    while (1)
    {
        new_socket = accept(server_fd, (struct sockaddr *)&client_addr, &client_len);
        if (new_socket < 0)
        {
            perror("server accept");
            close(server_fd);
            exit(1);
        }

        while (1)
        {
            // 5. 读取和写入数据
            char buffer[BUFFER_SIZE];
            int read_len = recv(new_socket, buffer, BUFFER_SIZE - 1, 0);
            if (read_len < 0)
            {
                perror("server recv");
                close(server_fd);
                exit(1);
            }

            if (read_len == 0)
            {
                printf("client close\n");
                close(new_socket);
                break;
            }

            buffer[read_len] = '\0';

            printf("recv client message: %s\n", buffer);

            char resp[1024] = {0};
            snprintf(resp, 1023, "server receive: %s", buffer);

            int write_len = send(new_socket, resp, strlen(resp), 0);
            if (write_len < 0)
            {
                perror("server send");
                close(server_fd);
                exit(1);
            }

            if(write_len == 0){
                printf("client close\n");
                close(new_socket);
                break;
            }

            printf("server send msg %s success!\n", resp);
        }
    }


    // 6. 关闭socket
    close(new_socket);
    close(server_fd);
}